Transplantation of organs has progressed from a risky experimental therapy to a safe and life-saving treatment modality in a relatively short span of five decades. However, transplant recipients require life-long treatment with non-specific, toxic, and multiple immunosuppressive drugs, and are ever under the threat of losing their allografts because of immune rejection of the transplanted organ.
Acute rejection of an organ transplanted from one human to another is an important risk factor for allograft failure. The outcome of acute rejection is, however, difficult to predict.
Currently, observation of histologic features in allograft tissue obtained by core needle biopsy is the best predictor whether an acute rejection will respond to anti-rejection therapy. However, the invasive procedure of allograft biopsy is associated with complications such as bleeding, arteriovenous fistula, and even graft loss. Thus, there is a need for a non-invasive method for determining whether a patient suffering from acute rejection of a transplant organ is at risk of loss of the transplanted organ.